Mineral oil composition containing a thenylamine



Patented Feb. 14, 1 950 UNITED STATES PATENT OFFICE MINERAL on. gggrosfion conrammo A Howard D. Hartough,

Pltman, and Sigmund J.

Lukasiewicz, Woodbury, N. J., assignors to So-' cony-Vacuum Oil Company, Incorporated, a corporation of New York plication January 29,

3 Claims.

The present invention relates to the condensation of thiophene and thiophene derivatives with formaldehyde and its polymers and ammonia andamines. In particular, the present invention relates to the production of thenyl amines (aminomethylthiophenes), subresinous bodies and resinous bodies by a reaction involving thiophene or alkylthiophenes or halothiophenes or alkoxythiophenes and the like, or in general compounds having an unsubstituted thiophene nucleus or compounds having stable electropositive substituents other than unstable (OH)- and (NH2)" groups attached to the thiophene nucleus, formaldehyde or its polymers and ammonium halide or amine salts. (The nomenclature employed herein is that of Steinkopf.

- Thus, in Die Chemie Des Thiophenes, [verlag von Theodor Steinkopf, Dresden und Leipzig (1941) lithographed by Edwards Brothers, Inc., Ann Arbor, Mich. (1944)] at page 5, Steinkopf discusses the nomenclature of thiophene compounds. In accordance therewith the radical is known as the thienyl radical and the group is known as the thienylen radical.)

Blicke and Burckhalter synthesized 2-thenyl amine by treating 2-(bromomethyl)-thiophene with hexamethylenetetramine (J. A. C. S. 64, 4'77 (1942). The product of this primary reaction was then treated with hydrochloric acid in the presence of ethyl alcohol to obtain 2-thenyl amine hydrochloride. The free amine had a boiling point of 73-75 degrees centigrade at 11 millimeters of mercury (l95200 C. at 760 millimeters of mercury). Putokhin and Egonova obtained 2-thenyl amine in yields of 50-55 per cent by reducing 2-thenyl oxime (C4H3SCH=NOH) with zinc dust and hydrochloric acid [J. Gen. Chem. (U. S. S. R.) 10, 2873 (1940) They reported that the free amine possessed the following physical properties: boiling point at 26 milli- 1947, Serial No. 725,160

2 meters of mercury-88 degrees centigrade (195 C. at 760 millimeters of mercury), D 4=1.1370 and refractive index, n n=l.5678. v

It has now been-found that 2-thenyl amine, di-(2-thenyl) amine and polymeric amines can be produced bythe condensation of thiophene with ammonium halide and certain amine hydrohalides by means of a highly reactive aldehyde such as formaldehyde. The following equation 10 generalizes the reaction:

The free amines can be obtained from the hydrohalides by standard procedures, for example, by treatment of the hydrochlorides with aqueous caustic followed by extraction with benzene from a saturated salt solution. Amine I and amine II have been isolated in the pure state by distillation in vacuum. Amine III decomposes when heated to temperatures exceeding 200-210 degrees centigrade with the loss of water.

It is to be noted that analyses of amine III and the chemical properties thereof indicate that it is a polymeric amine containing several units of the C4H3S.CHz-N=type. It is not a tri-(2- thenyl) amine because the sulfur content is too low while the nitrogen content and the molecular weight are too high for the trithenyl amine.

' Amines I and 11, i. e. 2-thenyl amine and di- 2-thenyl amine, respectively, are strongly basic, form addition complexes with carbon dioxide on K 4- 01110 max contact with air and dissolve rubber on contact. They may be distilled to a water-white product but soon show a yellow discoloration.

Amine III (the polymeric amine) is a weakly basic amine that can be freed of its hydrochloride by neutralization with sodium acetate. Amines I and 11 cannot be so freed. This characteristic indicates that amine 111 contains tertiary amine groupings. The presence of active hydrogen is evidenced by the fact that amine III gives a rela-- tively high hydroxyl number. An explanation for this can be found in presuming that amine 111 contains the following grouping:

Materials known to contain these groupings readily lose water and polymerize to form resinous bodies. Decomposition of resin III by heat results in the formation of resinous products with the liberation of water.

The formaldehyde to be used in this reaction may be in the form of an aqueous solution such as the conventional aqueous solution containing 36-40 per cent formaldehyde, known commercially as Formalin, or in the form of paraformaldehyde or trioxane. When polymeric forms of formaldehyde are used, it has been found advantageous to add a small amount, say a few milliliters of water or of an acid per mole of formaldehyde. The acid to be used is one with adissociation constant of about or less, such as acetic acid.

Hexamethylenetetramine when mixed with thiophene and hydrochloric acid slowly added gives rise to the same reaction and the same products as are obtained by condensing thiophene, ammonium chloride and formaldehyde. Thus, hexamethylenetetramine and hydrochloric acid may be substituted for formaldehyde and ammonium chloride.

Primary and secondary amines such as aniline and dibutyl amine in the form of their hydrochlorides may be substituted for the ammonium chloride. On the other hand, ethylene diamine,

compounds having a replaceable hydrogen attached to the nitrogen atom. Other objects and advantages will become apparent from the following description.

In general, the method for producing the thenyl amines and their derivatives involves reacting'thiophene or its derivatives as defined hereinbefore with formaldehyde or its polymers and a nitrogen compound having at least one replaceable hydrogen attached to the nitrogen 'atom. The reaction occurs to produce monoand di-thenyl amines and sub-resinous to resinous bodies dependent upon the nitrogen compound employed and the conditions under which the reaction takes place.

When ammonium halide, CHzO and thiophene or its derivatives having stable electropositive substituent groups other than the unstable hydroxyl or amino groups are reacted at temperatures below 100 degrees centrigrade for periods of time up to several hours, three products are obtained; to wit: primary amine, secondary amine and sub-resinous bodies of the nature of a tertiary amine. The proportion 'of each of these products in the final product can be controlled by controlling the mole ratio of the reactants. For example, employing Formalin, am-

monium chloride and thiophene the proportions of primary amine, secondary amine and subresinous body maybe controlled as shown in Table I. The results tabulated in Table I were obtained by heating the reaction mixture at about '70 to about 80 degrees centrigrade for about 1.5 hours. Thereafter the unreacted thiophene was removed, a diluent added to the residual liquid, ammonium chloride crystals removed, diluent removed, residual liquid neutralized with strong caustic in the presence of benzene. the neutralized liquid extracted three times with benzene, the benzene stripped off and the residue distilled in a vacuum. The fraction boiling between 190-205 degrees centigrade (corrected to 760 millimeters of mercury) was considered to be primary amine, that boiling at 250-291 degrees Centigrade (corrected to 760 millimeters of mercury) was considered to be secondary amine and the residue was the sub-resinous body.

urea and thiourea do not give the corresponding products.

Accordingly, it is an object of this invention to provide a method for producing 2-thenyl amine and di-2-thenyl amine. It is another object of the present invention to provide a method for producing derivatives of 2-theny1 amine and di-2-thenyl amine. It is a further object of the present invention to provide a method for producing sub-resinous and resinous bodies from thiophene and compounds containing the thiophene nucleus having stable electro-positive substituents other than hydroxyl [(OH)] or amino [(NH2)] groups attached to the thiophene nucleus, formaldehyde or its polymers and nitrogen The foregoing data show that the amount 0: sub-resinous bodies in the reaction product car he kept at a minimum by using an excess 0: thiophene and/or ammonium halide. Furthermore, that the amount of primary amine produced is substantially constant unless an ex cess of ammonium halide is used whether thi thiophene or the formaldehyde be in excess am that an increase in the amount of sub-resinou:

bodyappears to be correlated with the disap pearance of a proportionate amount of secondary amine.

The data in Table II show that the reactior takes place in a ratio of reactants of about 0.!

mol of thiophene for 1 mole of formaldehyd' audit 5 mole of ammonium halide, i. e. a mole ratio 1:21. These data show that within the limits examined the ratio of reactants does not vary appreciably from that set forth hereinbeiore regardless of the variationoi the original mole ratios. v

- e 1 I reduced'by employing an amount of ammonium halidein excess 0! the molar ratio 1:2;1, Thatis, ii the amount of ammonium halide employed is two or more'moles for each mole of thiophene and each two moles oi formaldehyde, the yield of primary and secondary amines is increased while Table II x I i Male! 0! Reactants Moles 01 mime-un- Recovered lizedin'lleaction M h 0 Run No. Mole Ratio 7 Ratio 7 cans 3%;3 mnci cinls omo Nmol oasis omo Nine! 4 2 1 1 0.0:025 2.9 0 0 1.1 2 1 1:2:1 5 a mu 1.0 0 1 4 1o 4 1=2.s=1 z 2 2 1=1=1 1.0 0 0.05 1 2 1.05 mm 4 2 2 21.1 3.0 0 v1.13 1 2 I101 1=2=1 While variation in the molar ratio of the rethe yield of sub-resinous amines is reduced. This actants does not cause any variation in the molar is demonstrated in'Table IV.

v I Table IV Moles oi Reactants Yield as per cent oi Ex- 1 Mole Moles oi theoretical ample Ratio Thio hene No. 041148 Aqueous NHACI Utl I 1 OHIO Amine 1 Amine II x111-.- 2 2 2 1:1:1 1.1 11 a IIL.--. 2 2.5 2.0 l:l.25:1 1.7 17 9 XII--- 5 10 5 1:2:1 14 7 XIV. 4 2 2 2:1:1 1.4 13 16 I 2 1.23 1.03 221:1 0.53 l3 12 X 1 1 3 11113 0.37 42 m 18.3

1 Formaldehyde provided by hexamethylenetetramine; 2 moles of aqueous hydrochloric acid added.

ratio of the reactants utilized, the variation of In order to'obtain the data presented in Table the molar ratio does cause a variation in the I molecular weight of the sub-resinous body as well as the proportion of sub-resinous body to the primary and secondary amines in the reaction product. The variation in molecular weight of the sub-resinous body with the variation in molar ratio of original reactants is demonstrated by the data in Table III.

(Those skilled in the art know that molecular weight determinations of this magnitude are subject to an experimental error of about :10 per pent.) Thus, when'formaldehyde is used in excess of the proportion 1:1: 1 the molecular weight of the sub-resinous body is increased. The subresinous body or amines are insoluble in alcohol, ether, chloroformand mineral oil and soluble in benzene and dioxane. The sub-resinous amines are viscous, light red to brown oils having an odor ofamines.

Although it has been demonstrated that variation in the molar ratio of the thiophene and formaldehyde does not cause any appreciable variation in the proportion of primary amine in the product unless an excess of ammonium halide is used, it has been found that the yield ot'primary amine and secondary amine can be increased and the yield of sub-resinous amines IV the reactants were mixed, brought to a reflux at about '70-'75 degrees centigrade and allowed to reflux for about one hour. The excess thiophene was removed by steam distillation. The residual oil was then fractionated in vacuo to obtain one cut boiling at 190-205 degrees centigrade (corrected to 760 millimeters of mercury) (primary amine) and a second fraction boiling at 250-291 degrees centigrade (corrected to 760 millimeters of mercury) (secondary amine). The yields were then calculated on the basis that the original amount of thiophene less the thiophene recovered as such is equal to the amount of thiophene which reacted. The per cent yield of each amine. was then calculated on the amount of thiophene which reacted.

While the'proportion of sub-resinous body can shown and refluxing the reaction mixture for three hours. The [reaction mixture was then neutralized and extracted with benzene. The yield of primary and secondary amines was very low. No formation of resinous products was observed. The crude sub-resinous amines were analyzed for sulfur, nitrogen and hydroxylgroup and the molecular weight determined. 'It is to be noted that aqueous formaldehyde was used. When aqueous formaldehyde is replaced by paraformaldehyde in these proportions only resinous materials are obtained. However, when the sub-resinous products listed in Table V are heated, hard resinous products are obtained. It is also to be noted that exposure of films of these period of matic petroleum stock containing tri-nuclear aromatic hydrocarbons which-are known to be Table V Moles oi Reactants Sub-resinous Amines Emmi) i ield P P Ml 6! 81' oec- S Aqueous NH Cl cent cent on ular s N. Weight x1x 1 1 0.5 59 20.6 5.65 235 125 xx. 1 3 1 01 22.9 6.21 100 620 xxx... 1 4 2 111 20.6 7.3 475 XII... 1 4 1 132 21.2 as 370 651 These analyses lead to the postulation that highly reactive was reacted with formaldehyde these sub-resinous amines may be represented by the empirical formula (C4HnS-(CH2) 2N)4(0H)4 where n equals zero to 3. The calculated values for sulfur and nitrogen, the hydroxyl number and molecular weight based on this formula, are

Per cent sulfur 19.2 Per cent nitrogen 8.4 Hydroxyl No. 340 Molecular weight 668 These values are to be compared with the .ob served values for the sub-resinous aminesproduced in Example I. The following formula may be said to represent the sub-resinous product obtained in Example II:

[(CiHnS) 3(CH2) 9N2(OH) 2] 1-2 where n equals zero to 3.

Calculated for Found Monomer (i. 2 6'. 2 Hydroxyl No l 252 199 Molecular Weight 428 (320 2-amylthiophene is condensed with formaldehyde and ammonium chloride, a produce is obtained which has a sulfur content of 19.3 per cent and nitrogen content of 2.85 per cent. This corresponds within experimental error with the sulfur content of 18.65 per cent and the' nitrogen content of 2.72 per cent of the tertiary amine represented by the formula (C5H10C4H3SCH2) 3N.

Thiophene is distinguished from benzene in at least one characteristic. Thiophene will react with secondary amines whereas benzene will not. For example, when one mole each of thiophene, formaldehyde and dibutyl amine hydrochloride are reacted, 27 grams of material boiling between 298 and 308 degrees centigrade at 760 millimeters I of mercury were obtained. Analyses of the mateand ammonium chloride in the same molar proportions, small amounts only, of the order of 1 to 2 per cent, of an amine were obtained.

The thenyl amines which are obtained by this method may be used as dye intermediates, antioxidants in lubricating oils, as insecticides, in the pharmaceutical industry as intermediates, and as intermediates in the production of other valuable materials.

The production of the thenyl amines and amines of derivatives is illustrated by the following non-limiting examples.

Example I A mixture of 56 grams (1.03 moles) of ammonium chloride, 168 grams (2 moles) of thiophene and grams (1.23 moles) of 37 per cent aqueous formaldehyde were heated for three hours at 74 degrees centigrade. One hundred and fifteen grams of unreacted thiophene were recovered by decantation. To the resulting reaction product, a thick red syrup, ethyl alcohol was added. The mixture was filtered to remove the unreacted ammonium chloride. (This step need not be included in the process when the amine III is desired since the amount of ammonium chloride used in the reaction can be controlled making recovery unnecessary). Ethyl alcohol was evaporated off on a steam bath and the thick red syrup neutralized with strong potassium hydroxide solution in presence of benzene. Three extractions with benzene from a saturated salt solution were necessary to remove the liberated amines. Benzene was stripped off and 42.0 grams of a dark brown oily liquid remained. Distillation in vacuo gave: 9.0 grams of 2-thenyl amine (I), B. P. 55- 65 degrees centigrade at 5 millimeters of mercury (190-203 degrees Centigrade at 760 millimeters), n 1.5650; 8.0 grams of di-(2-thenyl) amine (II), B. P. -145 degrees centigrade at 7 millimeters (250-291 degrees centigrade at 760 millimeters) n 1.5914; 25 grams of residue of unknown constitution.

Analysis: calculated for CsH'zSN (I), nitrogen 12.38 per cent; sulfur 28.35 per cent. Found, nitrogen 12.1 per cent; sulfur 27.1 per cent. Calculated for C10H11S2N (II), nitrogen 6.7 per cent. Found, nitrogen 6.17 per cent. Residue, found, nitrogen 6.97 per cent; sulfur 16.7 per cent.

Phenyl thiourea derivative of (I) three recrystallizations from alcohol, M. P. 121-1225 degrees centigrate (uncorrected). Calculated for nitrogen 11.3 per cent. Found, nitrogen 10.8 per cent. Oxidation of (I) with alkaline permam ganate gave 2-thiophene carboxylic acid, M. P. 129.5- degrees centigrade (uncorrected).

I. Yield of crude amine 112 grams. The nitrogen analysis of these crude amines gave 6.5 per Table VI 3 P o Percent N Percent S M. P., 90 3 fi Cale. Found Cale. Found 2-Thenyl stearamide 5- 3. 7 3. 9 z-Thenyl benzamide 121-122 6. 4 6. 3 Z-Thenyl acetamide 127-128 2-Thenylamine-benzaldehyde 142-144 6. 9 6. 3 z-Thenylurea 126-128 17. 9 15. 8 20. 5 21. 5 gym. Di-(z-thenyl) urea 152-156 11.2 11.1 25. 5 24.6 z-Thenyl phthalimlde I 25 5. 76 5. 65 Di-(Z-thenyl) Phthalamide 167 7. 81 7.86

1 All meltin points (uncorr.). Block met 0d.

Example II cent. Distillation in vacuo gave 17 grams of (I) To a mixture of 168 grams (2 moles) of thiophene and 70 grams (0.5 mole) of hexamethylenetetramlne equivalent to 2.5 moles of formaldehyde, 200 grams (2.0 moles) of aqueous hydrochloric acid was dropped into the reaction vessel during a period of forty minutes. The reaction mixture was kept for one hour at 76-80 degrees centigrade. Twenty-five grams of thiophene-were recovered by distillation. The reaction mixture was diluted with alcohol and filtered to remove the ammonium chloride. The alcohol was evaporated off and the concentrate treated with 100 grams of sodium hydroxide in 200 grams of water. The liberated amine was extracted with benzene. The benzene was stripped oil and distillation of the amine in vacuo gave: 33.0 grams of 2-thenyl amine (I), B. P. 192-205 degrees centigrade at 760 millimeters. amine (II), B. P. 260-280 degrees centigrade at 760 millimeters and 100 grains of residue.

Phenyl thiourea derivative of I, three recrystallizations from alcohol, M. P. 122-1225 degrees centigrade (uncorrected).

Example III To 129 grams (1 mole) of dibutyl amine, 100 grams (1 mole) of concentrated hydrochloric acid was added slowly to a flask cooled in ice. To the cold mixture 84.0 grams (1 mole) of thiophene and 81 grams (1 mole) of aqueous formaldehyde was added and heated for six hours at reflux temperature (80 degrees centigrade). sulting reaction mixture was neutralized with caustic, separated and dried. The product weighed 155.0 grams. Distillation in vacuo gave grams (17.4 per cent based on product charged to still) of material boiling 298-308 degrees centigrade at 760 millimeters.

Analysis: found, sulfur 21.3 per cent; nitrogen 8.67 per cent.

- Example IV An anhydrous mixture of 84.0 grams (1.0 mole) of thiophene, 30.0 grams (1.0 mole) of paraformaldehyde and 54.0 grams (1.0 mole) of ammonium chloride were heated for 1 /2 hours at reflux temperature. No reaction took place.

Example V A mixture of 252 grams (3.0 moles) of thicphene, 60 grams (2.0 moles) of paraformaldehyde, 108.0 grams .0 moles) of ammonium chloride and 20 grams of acetic acid were heated for three hours at 78 degrees centigrade. The procedure from here on is the same as in Example Sixteen grams of di-(Z-thenyl) The re- 7 grams of (II) and 84 grams of residue.

Analysis: calculated for C1oH11S2N (II); nitrogen 6.7 per cent; found; nitrogen 6.98 per cent. Residue; found; nitrogen 5.8 per cent; sulphur 28.3 per cent.

Example VI A mixture of 420 grams (5.0 moles) of thiophene, 120 grams (4 moles) of paraformaldehyde, 224 grams (4.1 moles) of ammonium chloride and 40 grams of acetic acid were reacted for 1% hours at 74 degrees centigrade. Two hundred and seventy-four grams (65.3 per cent) of thinphene had reacted. The reaction product was treated with 270 grams of crystalline sodium acetate dissolved in 300 milliliters of water. A benzene insoluble liquid was obtained which weighed 68.0 grams when dried on the steam bath.

Analysis; sulfur 17.40 per cent; nitrogen 5.19 per cent; chlorine 7.3 per cent.

The benzene soluble material was water washed two times and benzene stripped off. Yield 156 grams.

'120 grams (4 moles) of paraformaldehyde, 108

grams (2 moles) of ammonium chloride and 20 grams of acetic acid were heated for 1 /2 hours at 74 degrees centigrade. The reaction product was treated with a saturated aqueous solution of 200 grams of crystalline sodium acetate and 300 milliliters of benzene as in Example VI. The precipitated benzene-insoluble amine was treated with caustic solution and the free amine was dissolved in benzene. Benzene was stripped of! and the amine had the following analysis:

Sulfur 23.1 per cent; nitrogen 4.67 per cent; hydroxy No. 257; molecular weight 1123.

The other portion, benzene-soluble amine, when analyzed gave: sulfur 23.85 per cent; nitrogen 4.68 per cent; chlorine 1.7 per cent.

Example VIII A mixture of 77 grams (0.5 mole) of amylthiophene, 15 grams (0.5 mole) of paraformaldehyde,

27 grams (0.5 mole) of ammonium chloride and.

5 grams of acetic acid were reacted for one hour at 85 degrees centigrade. The refining procedure V was the same as in Example I. Distillation in vacuo gave 31 grams (91 grams theoretical) of a residue boiling 265 degrees at 760.1nillimeters.

Analysis: found, sulfur 19.3 per cent; nitrogen 2.85 per cent.

7 Example IX A mixture of 331 grams (3.94 moles) of thiophene, 60 grams (2 moles) of parai'ormaldehyde, 54 grams of ammonium chloride and 20 grams of acetic acid were heated for three hours at 77 degrees centigrade. Two hundred and forty-three grams of:thiophenewere recovered by distillayield is 130 grams assuming that 88 grams of .thiophene had reacted.

Distillation in vacuo gave: 13.4 grams of 2-thenyl amine (I), (10.3 per cent of theoretical); 109 grams of residue (84.0 per cent of theoretical), and 6.6 grams loss.

Example X A well stirred mixture of one mole (84 grams) of thiophene, one mole (81 grams) or aqueous 37 per cent Formalin solution, and 3 moles of ammonium chloride were brought to a reflux of 72 degrees centigrade In minutes a yellow coloration began to take place. The reaction mixture was allowed to reflux one hour and then 25 cubic centimeters of water were added. The condenser was arranged for downward distillation and the excess thiophene steam distilled off. In this manner 53 grams of thiophene was recovered and 33 grams (0.37 mole) of thiophene entered into the reaction. Rectification of the mixture by standard procedures gave 17.5 grams of 2-thenyl amine and 7.0 grams of di-(2-thenyl) amine as well as 23.0grams of residue. This corresponds to a 42 per cent yield of 2-thenyl amine and an 18.3 per cent yield of di-(2-thenyl) amine. I Example XI To 49 grams (0.6 mole) of thiophene and 48 grams (0.6 mole) of aqueous Formalin (36 per cent) were added 115 grams (1.2 moles) of ammonium zbromide. The procedure here was the same as in previous examples. 9 grams of 2- thenyl amine (I), 6 grams of di-(2-thenyl) amine (II), and 16 grams of residue (111) was obtained.

' Example XII A mixture of 420 grams (5.0 moles) of thiophene, 300 grams (10 moles) of trioxymethylene, 270 grams (5.0 moles) of ammonium chloride and 50 grams of acetic acid were refluxed for 30 minutes. A heat of reaction began and the temperature was maintained between 74-84 degrees centigrade by means of an ice bath. The reaction mixture was stirred for an additional hour during which time the temperature dropped to 46 degrees centigrade. ture was then added 500 cubic centimeters of 95 per cent alcoholand filtered to remove the precipitated ammonium chloride. The alcohol was evaporated and the 991 grams of concentrate were treated with 6 moles of sodium hydroxide, in a 40 per cent solution, in the presence of benzene. The liberated amine was thus extracted with benzene. The benzene was topped off and distillation of the amine in vacuo gave 81.5 grams of 2-thenyl amine (I), 36.5 grams of di-(2- thenyl) amine (II) and 413.5 grams of residue.

The yields of I and II are 14 per cent and 7 per cent of theoretical. respectively.

To the reaction mix-- 12 Example XIII A. mixture of 168 grams (2.0 moles) of thiophene, 60 grams (2.0 moles) of trioxymethylene, 108 grams (2.0 moles of ammonium chloride and 10 grams of acetic acid were reacted at the desired temperature, 74-84 degrees centigrade for 1 hours, 28 grams of thiophene were recovered. The refining procedure was the same as that in Example XII. The topped reaction product weighed 128.5 grams. Distillation of the free amine in vacuo gave 20 grams of 2-thenyl amine (I), 4.0 grams of di-(2-thenyl amine) (II) and 109 grams of residue.

The yields of I and II are 11 per cent and 3 per cent of theoretical,- respectively.

A vigorously stirred mixture of 336 grams (4.0 moles) of thiophene, 60 grams (2.0 moles) of trioxymethylene, 108 grams (2.0 moles) of ammonium chloride and 20 grams of acetic acid were heated at 74-84 degrees centigrade for 1% hours.

The refining procedure was the same as. in Example XII. Two hundred and seventeen grams of thiophene and 63 grams of ammonium chloride were recovered.

Distillation of the liberated amine in vacuo gave 20.0 grams of 2-thenyl amine (I) 23.0 grams of di-(Z-thenyl) amine and 77.0 grams of residue.

The yields of (I) and (II) are 13 per cent and 16 per cent of theoretical, respectively.

From the foregoing it will be recognized that thiophene and its alkyl derivatives react with aqueous formaldehyde and ammonium halides much more easily than with primary or secondary amine hydrohalides. It will also be evident that when polymerized forms of formaldehyde are used a small amount of acid such as acetic acid or, in general, an acid having a dissociation constant of 10- or less or any agent capable of depolymerizing the formaldehyde polymer, such as water, must be used. Furthermore, when hexamethylenetetramine is used, hydrochloric acid or one of the other hydrogen halides H Br or HI must be used. Accordingly, those skilled in the art will recognize that the production of high yields of primary and secondary thenyl amines involves reacting thiophene or its derivatives as defined hereinbefore with formaldehyde in the presence of at least 2 moles of ammonium chloride for each mole of thiophene at temperatures of degrees centigrade to reflux temperature for up to three hours, and preferably for about 1.5 to about 3 hours at reflux temperature. Aqueous formaldehyde can be replaced by its polymers or hexamethylenetetramine. However, when-the polymers of formaldehyde are used, sufficient acid must be present to depolymerize the polymer and when hexamethylenetramine is used, hydrohalide must be added.

A particular use has been discovered for the primary and secondary thenyl amines described hereinbefore. It has been discovered that these compounds can be used in lubricating oils to reduce or substantially completely inhibit the corrosion of bearings as indicated by the Bubble test. As those skilled in the art know, the Bubble test is described in many United States patents. for example, U. S. Patent No. 2,361,353.

The base or blank oil used in these-tests was Pennsylvania solvent-refined oil of 53 seconds 13 Saybolt Universal viscosity at 210 degrees Fahrenheit. The data present in Table VI showthat both the primary and the secondary thenyl amines are effective inhibitors at concentrations as low as 0.06 per cent of 1 per cent) by weight. Each test was carried out for 22 hours at 175 degrees centigrade.

While non-resinous primary and secondary thenyl amines together with sub-resinous nitrogprior art thermoplastic resins have been eniployed.

The production of these nitrogenous type resins is illustrated by the following non-limiting examples.

Eaample ,XV

A mixture of 168 grams (2 moles) of thiophenes,

" 107 grams (2 moles) of ammonium chloride and enous materials of the nature of tertiary'amines are produced by heating thiophene or derivatives thereof with formaldehyde or polymers thereof and ammonium halide (less readily with primary and secondary amines) for up to 3 hours at 75-80 degrees centigrade, essentially thermoplastic water-soluble'and water-insoluble nitrogenous resins can be produced by heating thiophone and its derivatives having stable electropositive substituents attached to the nucleus with formaldehyde or its polymers and ammonium halide or other substituted ammonias in the form of their halide salts for more than 3 hours at temperatures of 75-85 degrees Fahrenheit, or at the reflux temperature. Thus, when thiophene or alkyl thiophenes are heated formore than 3 hours, say 6 hours, with formaldehyde and ammonium halide or hexamethylenetatramine and hydrochloric acid or paraformaldehyde or trioxane, and acetic acid, the resins obtained by neutralizing the water solution are yellow to brown, thermoplastic, water-soluble resins. 0n the other hand, whenthe nitrogenous component of the reaction is an alkyl polyamine such as ethylene diamine or an aryl polyamine such as phenylene diamine, aniline or urea the resins produced are water-insoluble when in the form of the hydrohalides. That is to say, the waterinsoluble hydrohalides of these resins precipitate out of the aqueous reaction mixture as the reactions proceed.

Essentially the same end-products are produced whether aqueous formaldehyde in the form of Formalin (3'7 per cent aqueous formaldehyde), paraformaldehyde, or trioxane be used in this reaction. Hexamethylenetetramine and hydrogen halide acid canbe substituted for formaldehyde and ammonium halide to produce essentially the same end-products.

Thiourea when used to replace urea and the other nitrogenous components of thereaction fails to produce resinous products. However, yellow oils of objectionable odors are obtained. The sulfur content of these oils is indicativethat little or no thiophene has entered into the molecule.

The nitrogenous type resins described herein may housed in the common manner for which 200 grams (2.5) moles of 37 per cent aqueous formaldehyde were heated for six hours at 72 degrees centigrade. One hundred and thirteen grams (67.4 per cent) of thiophene'had reacted. The resulting product, a thick, red syrup was dissolved in ethyl alcohol and filtered. Ethyl alcohol was removed by evaporation on a steam bath followed by neutralization with potassium hydroxide solution. A brown resinous material precipitated out. The yield was 145 grams. The calculated yield was 169 grams.

Analysis: sulfur 24.9 per cent; nitrogen 6.98

per cent.

Example XVI To 93 grams (1 mole) of aniline cooled in ice, grams (1 mole) of aqueous hydrochloric acid was added. To the aniline hydrochloride salt, 84 grams (1 mole) of thiophene and 81 grams (1 mole) of aqueous formaldehyde were added and heated for six hours at reflux temperature (80 degrees centigrade). The thick syrup was diluted with alcohol and filtered. The solvent was stripped off and the residue neutralized with sodium hydroxide solution. A resinous product separated out which was washed with water and dried in vacuum desiccator. The yield was grams (calculated yield 172 grams).

Analysis: sulphur 1.03 per cent; nitrogen 10.4 per cent.

Example XVII To a mixture of 31 grams (0.5 mole) of urea, 41 grams (0.5 mole) of Formalin and 42 grams (0.5 mole) of thiophene, 50 grams (0.5 mole) of concentrated hydrochloric acid was added slowly while the mixture was cooled. A white solid precipitate formed immediately. After heating for six hours at reflux temperature only a trace of thiophene could be detected. The reaction mixture was filtered and the solid was washed with water, then with dilute caustic solution followed with two water washes. The resinous material was dried for 12 hours in a steam oven. The yield of resin as the hydrochloride salt was 93 grams.

Analysis: sulfur 14.2 per cent; nitrogen 20.6 per cent; chlorine 5.36 per cent.

Example XVIII illustrates the use of alkyl and aryl polyamines.

Example XVIII Example XIX Eighty-four grams (1 mole) of thiophene, 90 grams (1- mole) of paraformaldehyde "(equivalent to 3 moles of formaldehyde), 54 grams (1 mole) of ammonium chloride and 20 grams of acetic acid were mixed together in a 500 milliliter 3-necked flask fitted with a mechanical stirrer, thermometer, and reflux condenser and heated to 75 degrees centigrade. Within a few minutes yellow'to red coloration started and a vigorous heat of reaction set in necessitating ice bath cooling. After 1'5 minutes the heat of reaction subsided and the mixture was heated at 80-85 degrees centigrade for 2 hours thereafter. The material was cooled, transferred to a beaker, and neutralized with 40 per cent sodium hydroxide solution. A solid yellow to brown resinous mass precipitated. This was water washed on a rubber mill and the following analyses obtained:

Per cent sulfur 21.5

Per cent nitrogen 6.09 Per cent residual chlorine 0.31 Per cent ash- 1.0

Example XX Example V was repeated using 1 mole of thiophene, 1.3 moles of trioxymethylene, (equivalent to 4 moles of formaldehyde), 1 mole of ammonium chloride and 20 grams of acetic acid.

The following analyses were obtained on the resinous product:

Per cent sulfur 20.4

Per cent nitrogen 5.78 Per cent residual chlorine 1.00 Per cent ash 0.3

Example XXI molecular weight much higher than previous salts of hydrogen chloride, hydrogen bromide and hydrogen iodide, but not the salts of hydrogen fluoride.

This is a division of our application Serial No. 636,511 filed December21, 1945.

We claim:

1. A mineral lubricating oil containing a minor proportion, effective to reduce corrosion of bearings, of 2-thenylamine.

2. A mineral lubricating oil containing a minor proportion, effective to reduce corrosion of bearings, of di-(2-thenyl) amine.

3. A mineral lubricating oil containing a minor proportion, effective to reduce corrosion of bearings, of a thenylamine selected from the group consisting of 2-thenylamine and di-il-thenylamine.

HOWARD D. HARTOUGH.

SIGMUND J. LUKABIEWICZ.

REFERENCES CITED The following references are of record in the file of patent:

UNITED STATES PATENTS 

3. A MINERAL LUBRICATING OIL CONTAINING A MINOR PROPORTION, EFFECTIVE TO REDUCE CORROSION OF BEARINGS, OF A THENYLAMINE SELECTED FROM THE GROUP CONSISTING OF 2-THENYLAMINE AND DI-2-THENYLAMINE. 